Réunion Island marine biota comprise 4374 taxon records. Algae, scleractinians, hydrozoans, molluscs (except nudibranchs and cephalopods) and vertebrates are the better known taxa. Sponges, cnidarians (except hard corals and hydroids), crustaceans and echinoderms are zoological groups that need more investigations. Species diversity of ctenophores, platyhelminthes and others worms, lophophorates and tunicates is completely unknown. In order to increase accessibility to these records, taxa and species distribution data have been recorded in a new online interoperable database, developed by software engineers of Réunion University, and integrated in the information system of the coastal zone network project (Système d’information du Littoral, SIL). Rocky coasts constitute the largest coastal marine habitat of Réunion Island, but coral reefs have been more investigated. Among them, the Saint-Gilles/La Saline coral reef complex is the most studied area and the other reefs and platforms have been neglected so far. Further, hardly any studies exist for the rocky coast and the deep-water ecosystems. Although Réunion coral reefs shelter 191 species registered either in IUCN red list (2003), CITES, CMS and regional Nairobi conventions, the marine biodiversity and the coastal habitats are under increasing anthropogenic threats. In spite of the high species richness, the high number of threatened species and the numerous economic activities that depend of the health of coral reefs, no marine protected areas exist as yet in Réunion, mainly because of disagreements between stakeholders.